tolong bantu nomor 21,22,23,dan 27 pakek caranya

21.K = phi x d
= 3,14 x (25 x 2)
= 3,14 x 50
= 157 cm

22.L = 1/4 x phi x r x r
= 1/4 x 22/7 x 28 x 28
= 1/4 x 2462
= 616 cm2

23.K atas = 1/2 x phi x d
= 1/2 x 3,14 x 20
= 1/2 x 62,8
= 31,4 cm
K bawah = a + b + c + d
= 20 + 20 + 25 + 35
= 100 cm
K total = 31,4 + 100
= 131,4 cm

27. V = Luas alas x t
= 1386 x 20
= 27.720 cm 3